Electrically operated engine starter



June 1940- c. E. CLOUSTON 2,204,573

ELECTRICALLY OPERATED ENGINE STARTER Filed June 2, 1938 2 Sheets-Sheet 1I/VVENTOA HIS JTTOR/VE) June 18, 1940. Q CLOUSTQN 2,204,573

ELECTRICALLY OPERATED ENGINE STARTER Filed June 2, 1938 2 Sheets-Sheet 2mm E E Q a q mm W q a mm \A a on 4/ A 1 mm 8 a Q M Q Okcg rkai on/ hauntd 1..., 1940 V 2,204,573

UNITED STATES PATENT OFFICE Charles Edward (Houston, Osterley, England,as-

signor to Sperry Gyroscope Company, Inc New York, N. Y., a corporationof New York Application inne 2, 1938, Serial No. 211.425

In Great Britain June a, 1931 6 Claims. .(Cl. 290-48) The presentinvention relates to electrically there is mounted a clutch device 10which operated engine starters for internal combustion lut h s shaft 6!to th sle v As sh wn, engines and the like wherein an engine-en a ingone plate II of this clutch is fixed on the shaft member of an electricstarteris normally dlsenand anoth p ate 12 is s da along said gaged froma cooperating member on the engine h ft d i urged towards plate 7| b aSpring 5 starter-shaft, but is brought into engagement II which abuts atits farther end against a collar therewith at the time of starting. 14which is pinned to shaft 62. Between plates According to the presentinvention an elec- "II nd 12 h re is interposed the base of a D- c llyperated engine starter comprises a sinshaped member I5 which serves asan intermedigle electric motor which is effective bothto bring ateclutch plate, and is screwed to a disc 69 10 the starter and engine intooperative engagement secured to sleeve 41. Plates II, II, are shown andto crank the engine after engagement, and as faced with friction fabric,but clutch 10 may means enabling the starter clutch member to equallywell be of the type using steel and phosfollow-up the engine clutchmember should the p o -b Plates running in Due to the 15 engine overrunthe motor duringcranking. action of spring I3, a constant pressure isap- 15 Two embodiments of the invention will now pl d betw n u h platesI nd Causing be described by way of example with reference them to gripplate 15, and also to be centralized to the accompanying drawings, inwhich: on it; sleeve 41 and shaft 62 move together ax- Fig. 1 is avertical longitudinalsectional view ially, but are capable of relativerotation when of one form of the engine-starter according'to the clutchIII slips. 20 the invention; and Spring 35 abuts against a collar 33pinned to Fig. 2 is a vertical longitudinal sectional view shaft 62. Thewhole assembly of j clutch of a modified form of the engine starteraccordratchet clutch disc or body portion 25, shaft Y ing to theinvention. 42, sleeve 4] and armature 45 is normally held Referring nowto Fig. 1 of the drawings, the back by spring 32 so that the jaw clutchI is 25 electric motor 45 is arranged so as normally to out'ofengagement with the engine jaw clutch I. have its armature rearwardiyoffset from its field When current is supplied to the starter motorwinding so that energisation of the motor. re- 45, its armature is atonce pulled axially forsults in forward axial movement of its armature,wards into a central position relative to its field which movement isemployed for eflecting enmagnets, and jaw clutch I engages with the 30gagement of jaw clutches I. I'. Motor 45 has engine jaw clutch I'. itsarmature 46 provided with a hollow armature When the engine jaw clutchI' is engaged, the shaft 41 journalled at its rear end in a bearingresistance which it offers to turning, prevents 53' and splined at itsforward end upon a sleeve motor 45 from driving jaw clutch I through 48which, in turn, is splined to a tubular shaft sleeve 41, clutch-"I0 andshaft 62, since clutch in 35 49 that is journalled in anti-frictionbearings 54 is arranged to slip at quite moderate loads. and SI. Thestarter, however, drives engine jaw clutch Tubular shaft 49 transmitsthe torqueof the I, through the reduction gearing which turns motorarmature 46 to reduction-gearing of the 'sleeve 22', clutch disc 25 andratchet toothing type disclosed in the prior patent to Hollis Walter 25,this drive being at a low speed. Should the No. 2,152,005, dated March28, 1939, the final engine start up, the load on jaw clutch I will driveof which is ou ht out n Sleeve w c at once be removed, clutch disc 25will be overis splined p y Portion 25 0 t e Sta te run, and clutch IIIcease to slip, so that there law clutch. This portion 25 is con ecte ywill'be a direct high-speed driving connection atchet toot 26 t0 the eadP t 01 from armature 46 through shaft 41, clutch Ill, 45 the clutch, thehead I and body 25 of the clutch shaft '2 t jaw clutch I, The jaw clutchI is being held together y sp then driven at high speed to keep inengagement The h llow r ure h f 41 on which the with the engine, slipsimultaneously occurring at armature 46 of motor 45 is mounted, iscontinued the ratchet toothing 28. through the bearing 53', and hassecured thereto It may be remarked that during the initial 50 a disc orcollar 69. axial movement which brings jaw clutch I into The starter jawclutch I is secured to the lam engagement with the engine jaw clutch I,there gitudinal shaft 62 which extends right through may also berotation of the shaft 62 and jaw the motor and projects beyond the endof the clutch I. However the shock of engagement of 5 sleeve 41. On theprojecting end of shaft 4! rotating jaw clutch I with engine jaw clutchI' 55 is very slight, since the inertia of jaw clutch I and shaft 02 issmall. The slipping clutch II entirely insulates clutch I from theinertia eIIect of starter armature 46. Actually, very little rotationdoes actually take place in the circumstances mentioned, since the axialmovement is so rapid.

Figure 2 shows a modified form of the invention in which spring 32 ofFig. 1 is omitted, the starter jaw clutch I being held out of engagementwith jaw clutch I by a detent II pivoted on the electric motor housingat 11 and urged by a spring 18 against the inclined surface I! of theclutch housing ll, so that clutch II, and hence the armature l6 and thestarter jaw clutch I, are held out of engagement until and unless motor"is supplied with current, when the magnetic pull between armature 48and the field of motor overcomes the action oi detent "l8, and thestarter jaw clutch I is carried forward into engagement with the enginejaw clutch I; detent It then exerts no force to disengage the twoclutches I, I. This is advantageous since spring 32, shown in Figure i,might tend to throw jaw clutch I out oi engagement with law clutch I ifthe endwise magnetic pull between the motor field and its armatureweakened due. to a decreasein armature current with increase in armaturespeed.

Figure 2 also shows a modified form of all clutch 10, in which metalplates II and II, splined on shaft 82, are gripped between'metal plates82, 82' and t2" pressed by a spring I. Plates 82, 82 and 82" are splinedin the clutch housing in which plate ll, against which spring 83 abuts,is screwed. Plate u is locked in position by a screw arranged to lockthe screw threads of 84 together and thus prevent relative movementbetween members I. and II. A collar 85 and ball thrust 81 secure theshaft 02 to the clutch housing III and ensure that said shaft shall moveaxially with armature I, which is secured to clutch housing ll by adog-clutch 8! and a screwed sleeve It, the sleeve 8! being preventedfrom rotating by the pin II.

The body portion 25 of the starter jaw clutch i is shown as journalledin an anti-friction bearing 9i while spring I is provided with a thrustblock 92in the jaw clutch body 2!. Grease seals 98, 93 and 93" arefitted to retain lubricant in the gearing.

What I claimis:

1. An electrically operated engine starter comprising a single electricmotor adapted to drive (i) a starter clutch member through a Irictionclutch capable of slipping at a predetermined load, and (ii) a drivingmember for said starter clutch member operated through reductiongearing, said member being formed with ratchet teeth to enable theformerto rim faster than the latter and ratchet thereover but to enable thelatter to drive the former pomtively in one direction, the motor havingan armature which is rapidly moved axially upon energisation o! themotor and serves to bring the starter clutch member portion intoengagement with a clutch member on the engine shaft.

2.8tarteracoordingtoclaimlwhereinaxial movement 0! the armature is atall times opposed by a spring which tends to maintain the clutch memberthereon out of engagement with the engine clutch member.

3. Starter according to claim 1 wherein axial movement of the armatureto efiect engagement of the starterclutch member with the engine clutchmember is opposed by a spring-urged detent which permits such movementwhen the motor is energised and resumes its opposition to movement onlywhen the armature has been subiected to an opposite axial movement bythrust exerted between the starter and engine clutch members.

4. In an electrically operated engine starter of the jaw clutch type, astarting motor having a field, armature and shaft, a law clutch axiallymovable with said shaft, reduction gearing between said shaft and clutchfor normal cranking, and a'direct connection from said shaft to saidclutch including an overrunning device for maintaining the clutch teethin rotational engagement during the cranking, said armature being biasedto an out of line position with its field, whereby upon excitation ofsaid motor an initial endwise thrust of said jaw clutch to efi'ectengagement I -between said hollow shaft and said first mentioned law tosupply the requisite cranking torque to the engine.

6. In an electrically operated engine starter of the law clutch type, astarting motor having a field, armature and shaft, a jaw clutch axiallymovable with said shaft, reduction gearing between said shaft and clutchfor normal cranking. a direct connection from said shaft to said clutchincluding an overrunning device for maintaining the clutch teeth inrotational engagement during the cranking, and a spring urged detent fornormally maintaining said armature out of line position with its field,whereby, upon starting the motor, an initial endwise thrust of the Jawclutch to eiIect engagement with the engine is efi'ected, said detentresuming Tits opposition to such movement only when the armature hasbeen returned to its normal position by other means.

CHARLES EDWARD CLOUSTON.

